Afghanistan's president Hamid Karzai has called on Pakistan to help get the Taliban to peace negotiations, in a significant sign that Kabul is serious about bringing an end to the conflict.

Pakistan is seen as a major supporter of the Taliban and its co-operation is considered vital.

During a visit to Islamabad, Mr Karzai says he asked recently elected Pakistan prime minsiter Nawaz Sharif for his support for peace talks.

"We discussed...the issue of joint fight against extremism, and reconciliation and peace building in Afghanistan with the expectation that the government of Pakistan will facilitate... the peace process in Afghanistan, and in providing opportunities, or a platform, for talks between the Afghan High Peace Council and the Taliban movement," he said.

Mr Sharif says he gave a commitment to do anything within his power to achieve peace.

"I assured president Karzai that Pakistan will continue to extend all possible facilitation and the international community's efforts for the...realisation of this noble goal," he said.

"Pakistan would also help reinforce regional efforts in support of stabilisation of Afghanistan."

Some analysts have expressed scepticism about the latest meeting.

The Taliban refuses to deal with the Karzai administration, dismissing it as a proxy for the United States.

Mr Karzai's trip also comes after an attempt to start peace talks in Qatar's capital of Doha failed in June.

"We've seen over the years that's there been a lot of the right statements from both sides - from Pakistan and Afghanistan - saying yes, yes, we're both really committed to working together to promote peace," said Heather Barr, an analyst for Human Rights Watch based in Kabul.

"But I don't think the perception here is that that's actually led to very much."

Ms Barr says there are even doubts as to whether Mr Sharif can control the Pakistani intelligence service - the ISI - an agency viewed as the main conduit between Islamabad and the Taliban.

"One of the challenges, one of the questions about this meeting is does Sharif really have the power to decide what Pakistan's approach will be on dealing with the Taliban?" she said.

"Because they're real questions about to what extent Sharif himself is able to control the ISI and the other Pakistani Security bodies."

However, Mr Karzai also requested that Mr Sharif release a number of key Taliban leaders presently in Pakistani custody.

This is seen as a move that could dramatically improve the prospects of getting the Taliban to talk peace.